51644221066 has 4 divisors (see below), whose sum is σ = 77466331602. Its totient is φ = 25822110532.

The previous prime is 51644221039. The next prime is 51644221133. The reversal of 51644221066 is 66012244615.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 66012244615 = 5 ⋅13202448923.

It can be written as a sum of positive squares in only one way, i.e., 46089649225 + 5554571841 = 214685^2 + 74529^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12911055265 + ... + 12911055268.

Almost surely, 2^51644221066 is an apocalyptic number.

51644221066 is a deficient number, since it is larger than the sum of its proper divisors (25822110536).

51644221066 is a wasteful number, since it uses less digits than its factorization.

51644221066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25822110535.

The product of its (nonzero) digits is 69120, while the sum is 37.

The spelling of 51644221066 in words is "fifty-one billion, six hundred forty-four million, two hundred twenty-one thousand, sixty-six".